// Two-star problem // Problem 993 Product of Digits /* This program is written by Prof. Chua-Huang Huang Department of Information Engineering and Computer Science Feng Chia University Taichung, Taiwan Disclaimer: The programming problem is downloaded from UVa Online Judge (https://uva.onlinejudge.org/). The program solution is provided for helping students to prepare Collegiate Programming Examination (CPE). The author does not guarantee the program is completely correct to pass UVa Online Judge platform or CPE examination platform. This program is not intended for a student to copy only. He/She should practice the programming problem himself/herself. Only use the program solution as a reference. The author is not responsible if the program causes any damage of your computer or personal properties. No commercial use of this program is allowed without the author's written permission. */ #include #include #include int main(void) { int cases; // Number of cases; unsigned int N; // Input integer N. long long int Q; // The integer its product of digits is N, if there is one; otherwise, -1. int factor; int position; // digit position from left to right. int i; // Loop variable. scanf("%d", &cases); // Input the number of cases. for (i=0; i1) { // When the factor is 9, 8, 7, 6, 5, 4, 3, or 2, continue. if (N%factor==0) { // N has a factor of 9, 8, 7, 6, 5, 4, 3, or 2. Q += factor * pow(10, position++); // Add a digit to Q. N = N / factor; // Test N after take the factor out. } else factor--; // Test the next factor. } if (N!=1) Q = -1; // N cannot be the product of a set of digits. } printf("%lld\n", Q); // Output the result, Q. } return 0; }